From: Alekos Filini <alekos.filini@gmail.com>
Date: Mon, 26 Apr 2021 10:01:09 +0000 (+0200)
Subject: Use `parse_quote!()` to build complex syn::* objects
X-Git-Tag: v0.0.98~12^2~2
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=ldk-c-bindings;a=commitdiff_plain;h=dec732cefbdd97585b7de7fd4a9521f44f1580dd

Use `parse_quote!()` to build complex syn::* objects
---

diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs
index e217bab..e30bb16 100644
--- a/c-bindings-gen/src/main.rs
+++ b/c-bindings-gen/src/main.rs
@@ -25,6 +25,7 @@ use std::io::{Read, Write};
 use std::process;
 
 use proc_macro2::Span;
+use syn::parse_quote;
 
 mod types;
 mod blocks;
@@ -63,9 +64,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
 				writeln!(w, "/// Serialize the {} object into a byte array which can be read by {}_read", for_obj, for_obj).unwrap();
 				writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
 
-				let ref_type = syn::Type::Reference(syn::TypeReference {
-					and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
-					elem: Box::new(for_ty.clone()) });
+				let ref_type: syn::Type = syn::parse_quote!(&#for_ty);
 				assert!(!types.write_from_c_conversion_new_var(w, &syn::Ident::new("obj", Span::call_site()), &ref_type, Some(generics)));
 
 				write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
@@ -84,26 +83,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
 			},
 			"lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs" => {
 				// Create the Result<Object, DecodeError> syn::Type
-				let mut err_segs = syn::punctuated::Punctuated::new();
-				err_segs.push(syn::PathSegment { ident: syn::Ident::new("ln", Span::call_site()), arguments: syn::PathArguments::None });
-				err_segs.push(syn::PathSegment { ident: syn::Ident::new("msgs", Span::call_site()), arguments: syn::PathArguments::None });
-				err_segs.push(syn::PathSegment { ident: syn::Ident::new("DecodeError", Span::call_site()), arguments: syn::PathArguments::None });
-				let mut args = syn::punctuated::Punctuated::new();
-				args.push(syn::GenericArgument::Type(for_ty.clone()));
-				args.push(syn::GenericArgument::Type(syn::Type::Path(syn::TypePath {
-					qself: None, path: syn::Path {
-						leading_colon: Some(syn::Token![::](Span::call_site())), segments: err_segs,
-					}
-				})));
-				let mut res_segs = syn::punctuated::Punctuated::new();
-				res_segs.push(syn::PathSegment {
-					ident: syn::Ident::new("Result", Span::call_site()),
-					arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
-						colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
-					})
-				});
-				let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path {
-					leading_colon: None, segments: res_segs } });
+				let res_ty: syn::Type = parse_quote!(Result<#for_ty, ::ln::msgs::DecodeError>);
 
 				writeln!(w, "#[no_mangle]").unwrap();
 				writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
diff --git a/c-bindings-gen/src/types.rs b/c-bindings-gen/src/types.rs
index 80ad2af..85fd01c 100644
--- a/c-bindings-gen/src/types.rs
+++ b/c-bindings-gen/src/types.rs
@@ -15,6 +15,7 @@ use std::hash;
 use crate::blocks::*;
 
 use proc_macro2::{TokenTree, Span};
+use syn::parse_quote;
 
 // The following utils are used purely to build our known types maps - they break down all the
 // types we need to resolve to include the given object, and no more.
@@ -1457,15 +1458,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 				let tail_str = split.next().unwrap();
 				assert!(split.next().is_none());
 				let len = &tail_str[..tail_str.len() - 1];
-				Some(syn::Type::Array(syn::TypeArray {
-						bracket_token: syn::token::Bracket { span: Span::call_site() },
-						elem: Box::new(syn::Type::Path(syn::TypePath {
-							qself: None,
-							path: syn::Path::from(syn::PathSegment::from(syn::Ident::new("u8", Span::call_site()))),
-						})),
-						semi_token: syn::Token!(;)(Span::call_site()),
-						len: syn::Expr::Lit(syn::ExprLit { attrs: Vec::new(), lit: syn::Lit::Int(syn::LitInt::new(len, Span::call_site())) }),
-					}))
+				Some(parse_quote!([u8; #len]))
 			} else { None }
 		} else { None }
 	}
@@ -2397,15 +2390,10 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 						self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
 					} else { false }
 				} else if let syn::Type::Tuple(_) = &*s.elem {
-					let mut args = syn::punctuated::Punctuated::new();
+					let mut args = syn::punctuated::Punctuated::<_, syn::token::Comma>::new();
 					args.push(syn::GenericArgument::Type((*s.elem).clone()));
 					let mut segments = syn::punctuated::Punctuated::new();
-					segments.push(syn::PathSegment {
-						ident: syn::Ident::new("Vec", Span::call_site()),
-						arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
-							colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
-						})
-					});
+					segments.push(parse_quote!(Vec<#args>));
 					self.write_c_type_intern(w, &syn::Type::Path(syn::TypePath { qself: None, path: syn::Path { leading_colon: None, segments } }), generics, false, is_mut, ptr_for_ref)
 				} else { false }
 			},